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Fast Flashing 2004-021B



 
 
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  #21  
Old June 26th 04, 01:34 AM
PZeller66
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Default Fast Flashing 2004-021B

Thanks very much for taking the time to write and provide the link! If I'm
having problems with the Internet I usually assume it has something to do with
America Online.

I've enjoyed reading the posts on SeeSat-L and learned much from them, though
I admit I've barely started the learning curve when it comes to serious
satellite observing. My observing so far has been limited to finding
interesting objects on the Heavens Above site that are passing over my area and
then going out to look at them, making magnitude estimates (this is just second
nature to someone who has followed variable stars for years) and getting a
rough idea of the rotation period if the object I look at is flashing.

I'll try version 9.0 (or take the advice of friends and get a new ISP) and
see if this works, though I'm not sure that anything I report could be
considered good data yet.

Thanks again,

Paul Zeller
Indianapolis, IN
  #22  
Old June 30th 04, 11:13 AM
William R. Thompson
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Default Fast Flashing 2004-021B

Ed Cannon wrote:

By the way, besides Okean O Rk, quite a few other Zenits started
out as fast tumblers. They have all slowed down or even stopped.


Do you know if any of them have broken up before they slowed down?
I estimate that 2004-021B is spinning at 45 RPMs; if it's 11 meters
long and the axis is at its midpoint, then the ends experience a
centripetal acceleration of approximately 12 Gs. That seems
like a lot of stress for something that must have been built to
take lower accelerations.

I've tried to track down various Zenit-2 launchers through the
astronautix.com and heavens-above archives, but so far I've only
found one potential break-up candidate: 98-043, which may have
shed a few parts weeks after its launch.

Incidentally, I tracked 2004-021B a short while ago. It transited
Cygnus from my location, as did the Kosmos 2237 booster. They were
both heading north, with a separation of about 15 degrees, and almost
seemed to be flying in formation. It was a remarkable sight.

--Bill Thompson
  #23  
Old June 30th 04, 11:13 AM
William R. Thompson
external usenet poster
 
Posts: n/a
Default Fast Flashing 2004-021B

Ed Cannon wrote:

By the way, besides Okean O Rk, quite a few other Zenits started
out as fast tumblers. They have all slowed down or even stopped.


Do you know if any of them have broken up before they slowed down?
I estimate that 2004-021B is spinning at 45 RPMs; if it's 11 meters
long and the axis is at its midpoint, then the ends experience a
centripetal acceleration of approximately 12 Gs. That seems
like a lot of stress for something that must have been built to
take lower accelerations.

I've tried to track down various Zenit-2 launchers through the
astronautix.com and heavens-above archives, but so far I've only
found one potential break-up candidate: 98-043, which may have
shed a few parts weeks after its launch.

Incidentally, I tracked 2004-021B a short while ago. It transited
Cygnus from my location, as did the Kosmos 2237 booster. They were
both heading north, with a separation of about 15 degrees, and almost
seemed to be flying in formation. It was a remarkable sight.

--Bill Thompson
  #24  
Old July 1st 04, 02:10 AM
William R. Thompson
external usenet poster
 
Posts: n/a
Default Fast Flashing 2004-021B

William R. Thompson wrote:

Ed Cannon wrote:


By the way, besides Okean O Rk, quite a few other Zenits started
out as fast tumblers. They have all slowed down or even stopped.


Do you know if any of them have broken up before they slowed down?


Russel Eberst pointed out in an e-mail that the Kosmos 2227 booster
(92-093B) broke up into some two hundred pieces. If the Zenit-2
upper stage has been strengthened since then, it might not happen
again; on the other hand, it gives me a reason to keep watching
04-021B

--Bill Thompson
  #25  
Old July 1st 04, 02:10 AM
William R. Thompson
external usenet poster
 
Posts: n/a
Default Fast Flashing 2004-021B

William R. Thompson wrote:

Ed Cannon wrote:


By the way, besides Okean O Rk, quite a few other Zenits started
out as fast tumblers. They have all slowed down or even stopped.


Do you know if any of them have broken up before they slowed down?


Russel Eberst pointed out in an e-mail that the Kosmos 2227 booster
(92-093B) broke up into some two hundred pieces. If the Zenit-2
upper stage has been strengthened since then, it might not happen
again; on the other hand, it gives me a reason to keep watching
04-021B

--Bill Thompson
  #26  
Old July 3rd 04, 04:30 AM
PZeller66
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Posts: n/a
Default Fast Flashing 2004-021B

If the Zenit-2
upper stage has been strengthened since then, it might not happen
again; on the other hand, it gives me a reason to keep watching
04-021B


That's a really fascinating idea, Bill. Thanks, it gives me more reason to
track it as well!

Okean O (1999-039B) (25861) was an eye-catcher soon after launch. I was able
to see it just three weeks after it was launched in 1999, and it was flashing
like a strobe light! I went out to observe it after reading about it on H-A. I
sort of fell away from satellite observing for a while after that summer and
didn't observe it again until the spring of 2001. I saw it shining with a
steady brightness on that pass, and on eight or nine passes since then.

Can such a rapid tumble in an orbiting rocket stop after less than two years?
Or was I just catching this object at the wrong orientation every time and
missed any kind of flash period? I've always wondered this.

Paul Z
Indianapolis
  #27  
Old July 3rd 04, 04:30 AM
PZeller66
external usenet poster
 
Posts: n/a
Default Fast Flashing 2004-021B

If the Zenit-2
upper stage has been strengthened since then, it might not happen
again; on the other hand, it gives me a reason to keep watching
04-021B


That's a really fascinating idea, Bill. Thanks, it gives me more reason to
track it as well!

Okean O (1999-039B) (25861) was an eye-catcher soon after launch. I was able
to see it just three weeks after it was launched in 1999, and it was flashing
like a strobe light! I went out to observe it after reading about it on H-A. I
sort of fell away from satellite observing for a while after that summer and
didn't observe it again until the spring of 2001. I saw it shining with a
steady brightness on that pass, and on eight or nine passes since then.

Can such a rapid tumble in an orbiting rocket stop after less than two years?
Or was I just catching this object at the wrong orientation every time and
missed any kind of flash period? I've always wondered this.

Paul Z
Indianapolis
  #28  
Old July 3rd 04, 07:13 AM
William R. Thompson
external usenet poster
 
Posts: n/a
Default Fast Flashing 2004-021B

PZeller66 wrote:

If the Zenit-2
upper stage has been strengthened since then, it might not happen
again; on the other hand, it gives me a reason to keep watching
04-021B


That's a really fascinating idea, Bill. Thanks, it gives me more reason to
track it as well!


I looked at the sites Ed Cannon posted (thank you, Ed!) and compared
that against the debris lists on heavens-above. All of the Zenit-2s
seem to shed some debris: the covers over four solid separation
rockets. About a third of all Zenit-2s seem to have generated
more debris than this, so there's a fair chance that something may
happen.

If my calculations are correct, debris will be shed at a maximum of
25 m/sec (about 60 mi/hr). That doesn't lead to a major change
in orbit. Depending on the direction the junk flies off at,
the debris's new orbit will lower its perigee/raise its apogee by up
to 50 km, or change its inclination by about a fifth of a degree.

If there's a major bit of debris shed, I'd expect the booster's tumble
to slow as the debris carries off some momentum.

Okean O (1999-039B) (25861) was an eye-catcher soon after launch. I was able
to see it just three weeks after it was launched in 1999, and it was flashing
like a strobe light! I went out to observe it after reading about it on H-A. I
sort of fell away from satellite observing for a while after that summer and
didn't observe it again until the spring of 2001. I saw it shining with a
steady brightness on that pass, and on eight or nine passes since then.

Can such a rapid tumble in an orbiting rocket stop after less than two years?
Or was I just catching this object at the wrong orientation every time and
missed any kind of flash period? I've always wondered this.


I don't know how long it takes the tumblers to slow down; I think
it depends on several factors--their size and mass, and the
intensity of the Earth's magnetic field. As I understand it, magnetism
is the major factor in slowing a satellite's tumble; the spin sets up
eddy currents in the object.

--Bill Thompson
  #29  
Old July 3rd 04, 07:13 AM
William R. Thompson
external usenet poster
 
Posts: n/a
Default Fast Flashing 2004-021B

PZeller66 wrote:

If the Zenit-2
upper stage has been strengthened since then, it might not happen
again; on the other hand, it gives me a reason to keep watching
04-021B


That's a really fascinating idea, Bill. Thanks, it gives me more reason to
track it as well!


I looked at the sites Ed Cannon posted (thank you, Ed!) and compared
that against the debris lists on heavens-above. All of the Zenit-2s
seem to shed some debris: the covers over four solid separation
rockets. About a third of all Zenit-2s seem to have generated
more debris than this, so there's a fair chance that something may
happen.

If my calculations are correct, debris will be shed at a maximum of
25 m/sec (about 60 mi/hr). That doesn't lead to a major change
in orbit. Depending on the direction the junk flies off at,
the debris's new orbit will lower its perigee/raise its apogee by up
to 50 km, or change its inclination by about a fifth of a degree.

If there's a major bit of debris shed, I'd expect the booster's tumble
to slow as the debris carries off some momentum.

Okean O (1999-039B) (25861) was an eye-catcher soon after launch. I was able
to see it just three weeks after it was launched in 1999, and it was flashing
like a strobe light! I went out to observe it after reading about it on H-A. I
sort of fell away from satellite observing for a while after that summer and
didn't observe it again until the spring of 2001. I saw it shining with a
steady brightness on that pass, and on eight or nine passes since then.

Can such a rapid tumble in an orbiting rocket stop after less than two years?
Or was I just catching this object at the wrong orientation every time and
missed any kind of flash period? I've always wondered this.


I don't know how long it takes the tumblers to slow down; I think
it depends on several factors--their size and mass, and the
intensity of the Earth's magnetic field. As I understand it, magnetism
is the major factor in slowing a satellite's tumble; the spin sets up
eddy currents in the object.

--Bill Thompson
  #30  
Old July 6th 04, 03:44 PM
Paul Henney
external usenet poster
 
Posts: n/a
Default Fast Flashing 2004-021B

The slowing of the tumble is actually more to do with a conductor (the
rocket) rotating and moving in a magnetic field (the earths) and slowing
due to hysteresis effects..basically an induced current makes the rockets
tumble slow down over time.


pj



"William R. Thompson" wrote in message
...
PZeller66 wrote:

If the Zenit-2
upper stage has been strengthened since then, it might not happen
again; on the other hand, it gives me a reason to keep watching
04-021B


That's a really fascinating idea, Bill. Thanks, it gives me more

reason to
track it as well!


I looked at the sites Ed Cannon posted (thank you, Ed!) and compared
that against the debris lists on heavens-above. All of the Zenit-2s
seem to shed some debris: the covers over four solid separation
rockets. About a third of all Zenit-2s seem to have generated
more debris than this, so there's a fair chance that something may
happen.

If my calculations are correct, debris will be shed at a maximum of
25 m/sec (about 60 mi/hr). That doesn't lead to a major change
in orbit. Depending on the direction the junk flies off at,
the debris's new orbit will lower its perigee/raise its apogee by up
to 50 km, or change its inclination by about a fifth of a degree.

If there's a major bit of debris shed, I'd expect the booster's tumble
to slow as the debris carries off some momentum.

Okean O (1999-039B) (25861) was an eye-catcher soon after launch. I

was able
to see it just three weeks after it was launched in 1999, and it was

flashing
like a strobe light! I went out to observe it after reading about it on

H-A. I
sort of fell away from satellite observing for a while after that summer

and
didn't observe it again until the spring of 2001. I saw it shining with

a
steady brightness on that pass, and on eight or nine passes since then.

Can such a rapid tumble in an orbiting rocket stop after less than two

years?
Or was I just catching this object at the wrong orientation every time

and
missed any kind of flash period? I've always wondered this.


I don't know how long it takes the tumblers to slow down; I think
it depends on several factors--their size and mass, and the
intensity of the Earth's magnetic field. As I understand it, magnetism
is the major factor in slowing a satellite's tumble; the spin sets up
eddy currents in the object.

--Bill Thompson



 




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